Sorbitol Solution Research Articles

Evaluation of mechanical and rheological properties of metronidazole gel as local delivery system

Rosacea is a chronic multifactorial vascular skin disorder that affects about 10 percent of the general population. Metronidazole is an effective antibiotic in the treatment of moderate-to severe rosacea. Metronidazole is a suitable drug in cases of resistance to tetracycline or erythromycin, but it has also been shown that oral metronidazole may increase the side effects (e.g., peripheral neuropathy). Oral metronidazole should not be used for more than three months, and hence topical metronidazole gel is the best therapeutic choice in rosacea (especially during pregnancy). This study examined the mechanical (adhesiveness, cohesiveness, extrudability, spreadability, homogeneity) and rheological (viscosity), skin irritant and drug release properties of different metronidazole gel formulations that contain anionic emulsifying wax, glycerin and lactic acid in different proportions. The release studies were conducted using Franz diffusion cells and Silastic membrane as a barrier. The results indicated that gel compressibility, hardness, and adhesiveness, are the factors that influence the ease of gel removal from the container, ease of gel application onto the mucosal membrane, and gel bioadhesion. The findings showed that there exists a strong negative correlation between the spreadability of a formulation and its cohesiveness, the spreadability of a formulation is inversely proportional to its cohesiveness. However, sorbitol solution (70%) concentration was not significantly correlated with drug release. In addition, drug release was significantly reduced as the concentration of anionic emulsifying wax increased and the concentration of lactic acid decreased. The maximum metronidazole release was achieved at a pH of 4-6. Data obtained from in vitro release studies were fitted to various kinetic models and high correlation was obtained in the Higuchi and first order models. The results showed that all the gel formulations showed good extrudability, viscosity, cohesiveness, homogeneity and spreadability.

INTERCALATION OF SUGAR ALCOHOLS INTO THE INTERLAYER OF MONTMORILLONITE BY WET AND DRY PROCESSES

Organic and inorganic complexes are formed by the intercalation of ethylene glycol and glycerol into the interlayer of montmorillonite. Glycerol and ethylene glycol have the molecular formula C 2 H 6 O 2 and C 3 H 8 O 3 , respectively, and the general formula is C n H 2(n+1) O n . This formula represents a sugar alcohol group: erythritol for n = 4, xylitol for n = 5, sorbitol for n = 6, and so on. Complexes were produced by a wet process, in which erythritol, xylitol and sorbitol solutions, and montmorillonite, were mixed to a paste; and by a dry process, in which montmorillonite and erythritol, xylitol and sorbitol, in the solid state, were mixed by automatic agate mortar. X-ray diffraction, FT-IR and X-ray photoelectron spectroscopy analyses of the resulting complexes showed that erythritol, xylitol and sorbitol were intercalated into the interlayer of montmorillonite in both wet and dry processes. The resulting complexes also showed an increase in the basal spacing with increasing n (or molecular weight or carbon chains). The difference between the wet and dry processes lies in the d-spacing in each montmorillonite-sugar alcohol system. The d-spacing of the complexes formed by the wet intercalation process were about 0.4 nm larger than those formed by the dry intercalation process. This is the length of the longest part of the water molecule. In the wet process, the sugar alcohols were intercalated with water molecules, and the montmorillonite swelled, while it expanded in the dry process.

Optimising magnetic resonance imaging for preoperative staging and surgical planning in colon cancer at 1.5 tesla and 3.0 tesla.

395 Background: The aim of this study was to determine best technique for future preoperative staging and operative planning in colon cancer using MRI at 1.5T, and feasibility at 3.0T. Methods: 39 scans were performed in 4 healthy volunteers comparing bowel distension using different oral contrast techniques; no oral preparation, 1L of water, 1L of poly ethylene glycol (Klean-Prep), and 1L of 2.1% barium sulphate and 3.2% sorbitol solution (E-Z-Cat) at 1.5T. Bowel distension was scored blindly by 2 experienced radiologists. A further 35 scans compared image quality of T2-weighted pulse sequences; 2D-TrueFISP, 3D-TrueFISP, HASTE, 2D-TSE and 3D-TSE. Scans were scored for movement artefact, colon wall and colon mesentery visualisation. Signal to noise ratio (SNR) was calculated. Inter-observer agreement was assessed using Cohen's Kappa. Equivalent optimised protocols were derived at 3.0T and tested for feasibility. Results: Inter-observer agreement for scoring was good (kappa = 0.61-0.67). Sorbitol-barium sulphate gave significantly better small bowel distension than no oral preparation, water and Klean-Prep (mean score 3.8 vs 1.6, 2.2 and 1.9, p≤0.007). 2D TrueFISP sequences gave the highest mean score for scan quality, significantly better than 3D-TSE, 2D-TSE, 3D-TrueFISP and HASTE (mean 10.6 vs 3.2, 7.8, 7.7 and 7.4, p≤0.012). 2D-TSE sequences obtained best SNR, significantly greater than obtained using 3D-TSE (p=0.045). 3.0T sequences were comparable or superior. Conclusions: Colon imaging using MRI requires fast sequences and adequate bowel distension. Our observations indicate that 2D-TrueFISP and 2D-TSE sequences with 1L Sorbitol-Barium sulphate orally give the best T2-weighted images of the colon wall and adjacent structures for cancer staging at 1.5T; equivalent 3.0T protocols are possible. No significant financial relationships to disclose.

Simplified assay of diethylene glycol and ethylene glycol in various raw materials by capillary gas chromatography

The FDA has recently taken steps to reduce risks due to raw materials affected by economically motivated adulteration (EMA). One area of great interest is diethylene glycol (DEG) or ethylene glycol (EG) adulteration of glycerin, propylene glycol, and solutions of sorbitol, for which the USP monographs have recently been revised (1). Such adulterations have occurred many times and in many countries, including a tragic episode between November 2008 and January 2009 in which 84 children in Nigeria died after ingesting teething syrup contaminated with DEG (9,10). To eliminate this problem, the FDA has required manufacturers of finished products to assay and confirm that incoming glycerin, propylene glycol, and sorbitol solutions meet the USP limits, and the FDA/USP has incorporated such testing into the identity requirements of its updated monographs.Unfortunately, even though USP test procedures detail a simultaneous DEG and EG assay for these materials, different standard solutions are specified depending upon whether the incoming sample is glycerin, propylene glycol, or a sorbitol solution; in addition, a certain gas chromatography (GC) capillary phase is detailed for sorbitol solutions, while the assays for glycerin and propylene glycol use a different capillary phase, requiring column changeovers, separate GC systems, or front/rear column configuration. In addition, NF monographs for polyethylene glycols (PEG) and polyethylene glycol monomethyl ethers (MPEG) used in pharmaceutical products also require DEG and EG testing (detailing their own specific tests); three separate test procedures for these types of raw materials (the larger PEG-type polymers are assayed differently than their smaller counterparts), making assay at QC unwieldy.This paper describes a single, simple test procedure that is applicable to the simultaneous assay of DEG and EG in all types of the described raw materials, using one standard solution. The assay procedure involves straightforward isolation, trimethylsilylation, and simultaneous capillary gas chromatographic quantitation using capillary GC with flame ionization detection. Although the USP-NF limits are 0.10% DEG and 0.10% EG (and 0.25% total DEG plus EG for the PEG and MPEG products), in reality any EMA would be at levels significantly higher than that, as low-level illegal EMA would not be economically advantageous. The scope of this project was not to fully validate this technique for inclusion in USP-NF, but just to demonstrate its applicability for those wishing to utilize it or take it further.

Thermodynamics of the Interaction of a Homologous Series of Amino Acids with Sorbitol

The apparent molar volumes V2,φ, apparent molar isentropic compressibilities KS,2,φ, and enthalpies of dilution of aqueous glycine, alanine, α-amino butyric acid, valine, and leucine have been determined in aqueous 1.0 and 2.0 mol·dm −3 sorbitol solutions at 298.15 K. These data have been used to calculate the infinite dilution standard partial molar volumes V 0 2,m, partial molar isentropic compressibilities K 0 S,2,m, and enthalpies of dilution � dilH 0 of the amino acids in aqueous sorbitol, along with the standard partial molar quanti- ties of transfer of the amino acids from water to aqueous sorbitol. The linear correlation of V 0 2,m for this homologous series of amino acids has been utilized to calculate the contribution to V 0 2 of the charged end groups (NH + 3 ,C OO − ) ,t he CH 2 group, and other alkyl chains of the amino acids. The results for the standard partial molar volumes of transfer, compressibilites and enthalpies of dilution from water to aqueous sorbitol solutions have been correlated and interpreted in terms of ion-polar, ion-hydrophobic, and hydrophobic-hydrophobic group interactions. A comparison of these thermodynamic properties of transfer suggest that an enhancement of the hydrophilic/polar group interactions is operating in ternary systems of amino acid, sorbitol, and water.

Theoretical Investigation of Interaction of Sorbitol Molecules with Alcohol Dehydrogenase in Aqueous Solution Using Molecular Dynamics Simulation

The nature of protein-sorbitol-water interaction in solution at the molecular level, has been investigated using molecular dynamics simulations. In order to do this task, two molecular dynamics simulations of the protein ADH in solution at room temperature have been carried out, one in the presence (about 0.9 M) and another in the absence of sorbitol. The results show that the sorbitol molecules cluster and move toward the protein, and form hydrogen bonds with protein. Also, coating by sorbitol reduces the conformational fluctuations of the protein compared to the sorbitol-free system. Thus, it is concluded that at moderate concentration of sorbitol solution, sorbitol molecules interact with ADH via many H-bonds that prevent the protein folding. In fact, at more concentrated sorbitol solution, water and sorbitol molecules accumulate around the protein surface and form a continuous space-filling network to reduce the protein flexibility. Namely, in such solution, sorbitol molecules can stabilize a misfolded state of ADH, and prevent the protein from folding to its native structure.

Comparison between DSC and TMDSC in the investigation into frozen aqueous cryoprotectants solutions

Purpose: The influence of thermal parameters in the observation of thermal events and in the calculation of heat transformation in aqueous cryoprotectant solutions after freezing was investigated using conventional differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC), respectively. Methods: The systems under study were formed by pure water and diluted aqueous solutions of mannitol, trehalose, sucrose, sorbitol, and glycine. The influence of different combinations of frequency and amplitude was analyzed in heating–cooling and heating-iso TMDSC scans. Results: Trehalose, sucrose, and sorbitol present a lesser critical temperature of primary drying than other cryoprotectants studied. The calorimetric variables selection is crucial to detect or not the thermal events, or to detect so with different numerical values. Then, the values of the calorimetric parameters determined are different if measured in a mode of heating–cooling or heating-iso. The TMDSC method-1 used in this study employs a higher number of cycles in each thermal event. The use of Lissajous figures and the study of the Cp in-phase signal evolution will allow us to understand the complexity of the events detected. Conclusions: The comparative study of both techniques points to the selection of conventional or modulated technique depending on the type of system and the nature of the studied events.

Modeling of Total Soluble Solid and NaCl Uptake during Osmotic Treatment of Bell Peppers under Different Infusion Pressures

The uptake of sorbitol and sodium chloride in slabs of green bell pepper (10 × 10 × 2 mm) osmotically dehydrated at different concentrations of sodium chloride (30, 40, and 110 g/L) and sorbitol (7°Bx, 24°Bx, and 41°Bx) at different pressures (4.05, 44.66, and 85.33 kPa) with infusion times ranging from 6 to 60 min for sorbitol and up to 36 min for NaCl was evaluated. Models that describe the uptake of these solutes were developed under different experimental conditions. A completely randomized 3 × 3 factorial design was used to study the effect of the process variables on uptake of solutes for both sorbitol and NaCl. The uptake kinetic of solutes for both sorbitol and NaCl increased to an asymptotic level with both solution concentration and pressure. A negative exponential model adequately fitted the kinetics for both solutes with R 2 = 0.97 and 0.94. The best conditions for the highest increase in total soluble solids during sorbitol solution infusion were 4.05 kPa of pressure and 16 min of immersion. NaCl uptake in peppers followed an exponential trend without reaching the equilibrium conditions. The fitted models were found adequate to estimate that the increase in total soluble solids and NaCl in bell peppers during osmotic process can be used to establish pretreatment conditions in the drying process.

Evaluation of acidity and total sugar content of children′s popular beverages and their effect on plaque pH

In the developing countries, dental caries has increased with the increased exposure to dietary sugars. There is no data on the cariogenicity and acidogenicity of popular beverages in the Syrian market. To investigate the endogenous pH, titratable acidity, and total sugar content of popular beverages (cola, orange juice, and full-fat milk), and assess plaque pH drop after consumption. Twenty-five healthy children with a mean age of 11.8 ± 0.6 years were recruited for this single blinded study. The pH of beverages was measured by a digital pH meter and the titratable acidity was expressed as the volume of 0.1 N sodium hydroxide required to neutralize the beverage. The total sugar content was estimated using High Performance Liquid Chromatography. Children rinsed with 15 mL of each of the beverages for 1 min. The controls used were 10% sucrose and 10% sorbitol solutions. The plaque pH was assessed before and after rinsing. Statistical analysis was performed using analysis of variance followed by Bonferroni test to assess minimum pH, maximum pH drop, and the area under curve. P value was set as 0.05. Both cola and orange juice had a low pH and similar total sugar content in contrast to the high pH and low sugar content of milk. Cola and orange juice were not statistically different from 10% sucrose (P > 0.05), but different from 10% sorbitol (P < 0.05), in contrast to milk, for all the parameters studied. Cola and orange juice are cariogenic/acidogenic and frequent intake should be discouraged. A reasonable intake of unsweetened milk may be advised safely.

High frequency shear ultrasonic properties of water/sorbitol solutions

Dynamic viscoelastic properties ( G′ and G′′), ultrasonic shear velocity and attenuation were measured for aqueous solutions of sorbitol at 5 MHz. For pure sorbitol, the shear ultrasonic velocity reached 1470 m s −1 with a density of 1500 kg m −3, consequently leading to a high acoustical impedance compared with “classical” polymers (polystyrene, nylon, polyethylene, Teflon, etc.). We demonstrate that this surprisingly high shear ultrasonic velocity for a viscoelastic material was due to the fact that the glass transition begins at a concentration above 85% of sorbitol in water. Hence, pure sorbitol is an ideal coupling material for high frequency shear experiments.

Thermodynamic study of the influence of polyols and glucose on the thermal stability of holo-bovine α-lactalbumin

Thermal stability of bovine α-lactalbumin in buffer and dilute aqueous solutions of erythritol, xylitol, sorbitol, inositol and glucose was evaluated by fluorescence spectroscopy and circular dichroism. Results show that at the selected conditions, the transition is reversible and is well described by a two-state model. At low concentration the cosolutes do not show a structure stabilizing effect, and some of them even destabilize the protein. At higher concentration, all of them stabilize the native protein conformation; however, the extent of stabilization is lower than the effect shown with other proteins, presumably due to the lactalbumin incomplete unfolding.

Investigating the processes necessary for satisfactory freeze-drying of waterlogged archaeological wood

Preliminary studies into methods for improving and safeguarding the preservation of waterlogged archaeological wooden artefacts are presented. Mannitol, sorbitol and trehalose have been tested as replacements for polyethylene glycol (PEG) as a treatment prior to freeze-drying of wooden archaeological objects. The highest anti-shrink efficiency achieved in this short experiment was (70 ± 15) % using a 20% weight per volume solution of sorbitol after soaking for one week. The collapse or eutectic temperature of each solution used was determined using a freeze-drying microscope. Importantly, it was noted that the collapse temperature of the solutions was reduced by several degrees after use for treatment of the wood samples for one month. A freeze-drying microscope with a cold light source has been used to observe the real-time freeze-drying behaviour of various treatments inside a thin section of wood, confirming that this novel technique is indeed possible and useful. Lastly, the effects of magnesium phytate as an iron chelator have been studied. It was found that the treatment lowers the collapse temperature of a PEG 600/2000 solution by roughly 3 °C meaning that objects must be freeze-dried at a correspondingly lower temperature. Iron K-edge X-ray absorption near-edge spectroscopy analysis showed that the treatment extracted approximately half of the iron(III) ions present in the timbers.

The effect of casein and calcium containing paste on plaque pH following a subsequent carbohydrate challenge

Objectives Previous research has shown that regular use of CPP–ACP increases calcium and inorganic phosphates in plaque and reduces enamel mineral loss. The aim of this study was to investigate if a CPP–ACP-containing paste would neutralize acidic challenges in dental plaque following sucrose rinse. Method Plaque pH was measured on 15 subjects in a cross-over study with and without prior application of the paste and with and without CPP–ACP. On each occasion, subjects rinsed with 10% sucrose and sorbitol solutions for 2 min in randomized order. Results The results showed the median lowest pH without paste was 4.8 (IQR: 4.7–5.0) and with mousse 5.6 (IQR: 5.5–5.6 and p < 0.001). The median lowest pH was 5.0 (IQR: 4.9–5.3) without CPP–ACP and with CPP–ACP was 5.8 (5.6–6.1 and p < 0.001). The time that pH remained below 5.7 and the time to return to resting pH showed similar differences in all subjects ( p < 0.01). Conclusion The results indicate that prior application of a CPP–ACP-containing paste reduced the fall in plaque pH following a sucrose challenge.

Ultrasonic properties of water/sorbitol solutions

Ultrasonic longitudinal velocity and attenuation were measured for aqueous solutions of sorbitol at approximately 5 MHz. For pure sorbitol, the ultrasonic velocity reached 3200 m s −1, consequently leading to a high acoustical impedance (around 5 × 10 6 Rayleigh) and good matching between the ultrasonic transducers and material samples.

A Highly Thermosensitive and Permeable Mutant of the Marine Yeast Cryptococcus aureus G7a Potentially Useful for Single-Cell Protein Production and its Nutritive Components

The highly thermosensitive and permeable mutants are the mutants from which intracellular contents including proteins can be released when they are incubated both in the low osmolarity water and at the nonpermissive temperature (usually 37 degrees C). After mutagenesis by using nitrosoguanidine, a highly thermosensitive and permeable mutant named Z114 was obtained from the marine yeast Cryptococcus aureus G7a. Of the total protein, 65.3% was released from the mutant cells suspended in distilled water after they were treated at 37 degrees C overnight. However, only 12.3% of the total protein was released from the mutant cells suspended in 1.0 M sorbitol solution after they were treated at 37 degrees C overnight. We found that intracellular density of the mutant treated at 37 degrees C was greatly decreased, and cell volume of the mutant treated at 37 degrees C was increased due to the increased protein release. However, no significant changes in the intracellular density and cell volume of the mutant were observed when its cells suspended in 1.0 M sorbitol solution were treated at 37 degrees C. It was found that no big changes in cell growth, protein content, vitamin C content, nucleic acid content, fatty acids, and amino acid compositions of both the mutant and its wild type were detected. Therefore, the highly thermosensitive and permeable mutant still can be a good candidate as single-cell protein. This means that the method used in this study is a simple and efficient way to release protein from the highly thermosensitive and permeable yeast mutant cells with high protein content.

Application of wavelet transform coupled with artificial neural network for predicting physicochemical properties of osmotically dehydrated pumpkin

Since physical properties including deformation and color changes are important attributes of a food product and are generally used by customers to decide whether to buy or consume the product, the ability to predict the physical properties of a food product subjected to different drying methods and conditions, hence the ability to optimize the drying processes, are of great interest. The objectives of this research were to predict the moisture content, product deformation and color changes (Δ E) of osmotically dehydrated pumpkin undergoing hot air drying via the use of combined wavelet transform-artificial neural network. A multiple layer feed-forward neural network was established to predict the physical properties based on inputs of wavelet coefficients and drying time. Several pre-osmosed solutions were used including sorbitol, glucose and sucrose solutions. Optimized ANN models were developed for sorbitol, glucose and sucrose solutions based on 1–2 hidden layers and 10–41 neurons per hidden layer. ANN models were then tested against an independent dataset. Measured values of moisture content, deformation, in terms of the so-called Heywood shape factor, and Δ E were predicted with R 2 > 0.9957 in all cases, except when pumpkin was osmotically dehydrated with glucose. The WT-ANN models were found to estimate the Heywood shape factor and Δ E with%MRE smaller than the ANN models alone in most cases.

Influence of NaCl and sorbitol on the stability of conformations of cytochrome c

Influence of ionic (NaCl) and non-ionic (sorbitol) additives on structural transitions of cytochrome c was investigated by circular dichroism, optical and EPR spectroscopy. Transformations of cytochrome c, induced by the acidification of solution and temperature perturbation, were monitored in the heme pocket together with changes in the secondary structure. NaCl and sorbitol exhibited antagonistic effect on the acid-induced transition of the protein. Sorbitol enhanced the stability of native conformation while NaCl destabilized this state. The midpoints of acid-induced transitions in the axial coordination of heme as well as in the secondary structure occurred nearly at the same pH values. However, temperature-induced transitions in the unfolding of the secondary structure were almost coincidental with the cleavage of Met80–Fe bond only in the sorbitol solutions. In the salt solution the Met80–Fe bond was markedly more labile than the secondary structure.

IMAGE ANALYSIS AND DYNAMIC MODELING OF THIN-LAYER DRYING OF OSMOTICALLY DEHYDRATED PUMPKIN

This study was conducted to investigate the effect of osmotic dehydration as a pretreatment on hot-air drying kinetics of pumpkin, to evaluate the best model for hot-air drying of pumpkin and to apply a computer vision system to study the color changes during drying. Pumpkin cubes were treated in 50% w/w sorbitol or sucrose solutions at 50C for up to 6 h, followed by hot-air drying at 60C and air velocity of 1 m/s. Drying data were fitted to 11 drying kinetic models. The goodness of fit was determined using the coefficient of determination (R2), reduced chi square (χ2), root mean square error (RMSE) and percent mean relative deviation modulus (E%). Hot-air dried samples pretreated with sorbitol had an improved lightness (higher L* values) compared to the hot-air drying while that pretreated with sucrose exhibited lower L* values. The total color changes (ΔE* values) increased during drying in a sequence ofΔE*sucrose solution < ΔE*sorbitol solution < ΔE*sucrose+hot air & < ΔE*sorbitol+hot air. PRACTICAL APPLICATIONS The combined treatment of pumpkins using osmotic dehydration followed by hot-air drying may provide a practical method for the preservation of pumpkin and the production of dehydrated pumpkin products.

Use of Artificial Neural Network and Image Analysis to Predict Physical Properties of Osmotically Dehydrated Pumpkin

The objectives of this research were to predict, using neural networks, the color intensity (ΔE), percentage of shrinkage as well as the Heywood shape factor, which is the representative of deformation, of osmotically dehydrated and air dried pumpkin pieces. Several osmotic solutions were used including 50% (w/w) sorbitol solution, 50% (w/w) glucose solution, and 50% (w/w) sucrose solution. Optimum artificial neural network (ANN) models were developed based on one to two hidden layers and 10–20 neurons per hidden layer. The ANN models were then tested against an independent data set. The measured values of the color intensity, percentage of shrinkage, and the Heywood shape factor were predicted with R2 > 0.90 in all cases, except when all the drying methods were combined in one data set.

Elution and internal migration of free amino acids in fish meats by soaking in sodium chloride or sorbitol solution

Elution and internal migration of free amino acids (FAA) in fish meats by soaking were investigated when the meat strips were soaked in various concentrations of sodium chloride (NaCl) or sorbitol solution. Rapid decrease of FAA in an earlier phase of soaking was followed by a mild one, irrespective of the kind and the concentration of soaking solution. The loss of FAA by soaking in NaCl solution was slightly larger than that in sorbitol solution. However, regardless of the kinds of soaking solution, the elution of FAA from fish meats by soaking was only dependent on the soaking time, independently of the concentration, namely osmotic pressure of the soaking solution. Conversely, sluggish migration of FAA from the inside to the surface of the meat strips proceeded by soaking. These results suggested that the elution of FAA from fish meats by soaking was driven by a simple diffusion from the surface of the meats to soaking solution, but it was regulated by sluggish migration rate of FAA in fish meats.